Article of manufacture



March 8, 1932. B. H'EYMANN 1,848,173

ARTICLE OF MANUFACTUR E Filed April 23, 1928 INVENTOR.

' Patented Mar, 8, 1932' "UNIT-EU "STATES BRUNO mm, 015 SAN FRANQISCOAGALIFORNIARQQ V ARTICLE OF MANUFACTURE? Application filed April 23, 19281 stamina: 272,040."

' "second degree without being a surface of revolution on any single axis.

The invention herein disclosed is directed to dies, punches and the like as articles of manufacture and which may be employed for the production of such surfaces and par- 7 ticularly such thin surfaces of metal or other rigid material as a foundation for the formation of reflectors as employed in headlights, beamprojection apparatus and the like. In the formation of such a reflector surface 1 it is customary to employ a convex punch or die and a concave die between which the thin metallic surface is formed as by press- 7 ing orcasting. The convex side of the said metallic surface takes on the form of the concave die and the concave side of the surface takes on the formof the convex die or punch; The latter is the more important as on it is preferably formed the reflecting surface for the proectorr c J The thin metal may also be formed by forcing against one of my from the opposite side. The accurate form of the convex and concave surfaces istherefore a matterof vital importance in theproduction of such a reflector and tools as dies and punches for thesesurfaces may be produced by, the ma- 'chine of my invention set forth above.

In such dies heretofore, there is an axis of symmetry whereas in the dies of my present invention while there may be a plane of symmetry, there is no axis of symmetry.

4 The dies of my invention may be employed in any conventional press or other machine to form the desired surface between them.

In my present invention the forming surfaces of the said dies are in each case the en- -velope of consecutive intersections of a famdies by fluid pressure ily 'f of conicoids of revoluti'en :and may be producett by the maehineeafuili described in: theabeVsrm-isitldapplication =to wh reh ref ereneeeisherein made.1 j I T Referring to the drawings wherein isset forthcertain specific forms -ofimy in vntion particularly suited'to produce rflection sF-igk 1 is -ai' vertical centrat longitudinalasection through a; pai p of dieswherein tkieconvex aria concave surfaQes are:formsd by an infinite e number of points whose locus is -theen velope ofi e nseoufivei intersectio s: ofa; mity of conieoids;oi revelutiomhaving fVa-riabIe -pa rameters withflaj pencil of pIaness- 7 I Fig: 2* issa horizsntahseetiionsoflEigr-l on f theline II II thereOfQ 1 V v 'Fig1 '-3 is a sectiom sim: aI tO -Eig l of the concavefidieiand Fig 1 's" aside view of ithe convex die or pfunchipf Eig. v z 1 Eigs. 5iancl 6armperspecti vevvfewszofithiniwo meta-Him:surfaces1 tlratrhavetbeemzformedrin .Eigrurte fi' is an raltennate': formuofim yuinven-m tiom'awherein the foim'i ngiqstlrfacesz of the; dies care: envelopes'sofwa*familyrof ,,ellipsoi;ds: oft-revolution; ofrvarying 'parameters: 1

Figsfiiis asperspective,vievw'ofetheiconvemi diefofiiFigs/i-TanduEigafif is a thin metal fie-r1" gectiigzusurface formedabetweem theidiess'ofs tlgn a; r 1 v i i Inotheiproduction? -z0tfi reflectors:v fromrmyi Y dies' therli-ght sourcew itli;whiehcthejearsstoe be employed is tozbe-locatd at thesai decomrs monzfocussresultingzinsarrefiection'ofthesaidz lightsourca fromzevery pointlonsthecreflectoras5 surface predeterminednbeamnarrayn ands= therefore thezilliiminatiomofa predetermined; area by the said beam array.

. Throughouteathe' rfigure'ss similar :numerals referzto'identicalpants: 1 1

, Referring; tor Eigislitheanumeral indi-r cate's the Econcav dievandlthl numeralefl? their;

2 convex dierinaassembledw positionawithl, the x2 space: 3;;" therebetween andciniiwhichathe reflector onzothensurface:is i'ifitbefflmedaf' -T IThe; space 3?indicatingzthersai-d lthicltness instherfigures'exaggeratechtorbettenaillusa-c traterzzthexclearancembetweenotheiitrwoirdie The inner or concave diersumfaoezatit in thef I i die is: formed:{substantiallysymmetricalc 10G in there is a common with and as substantially parallel with the convex surface 5 of the convex die 2. This die surface 5 is the counterpart of the desired finished reflector surface.

When a piece of thin metal has been formed in the space 3 between the surfaces 4, 5, the form shown in Figs. 5 and 6 is the result and the inner surface of this formed reflector then has the characteristics of the combination of the varying conicoids wherein the said conicoids all have one focus in common.

In Fig. 7 the concave die 13 has a, surface at 10 to form the back of a thin metallic reflector in the space 16 and the surface 11 of the convex die 12 formsthe reflector surface the thin metal being formed in the space 16 as before. The thin metal after being formed between the dies of Fig. 7 has the appearance shown at 15 in Fig.9.

Its reflecting surface 12 which has been formed against the concave surface 11 embodies the characteristics of an envelope of variable conicoids above specified, and wherefocal point forall of said conicoids.

.Referring to Fig. 4, 20 is one point on my surface and 21 is, a second. The vertical line 23, 24 is forward of the focal point 25. The distance 20,25, plus 20, 26 is, in my surface, equal to the distance 21, 25 plus21, 27 In Fig. 8, the curved line 30, 31 is forward of the focal point32. upon the surface. The distance32, 33 plus 33, 35 is equal to the distance 32, 34, plus 34, 36.

In the reflecting surfaces formed from tools here illustrated every point on such surface is positioned such that the sum of its distances from the common focalpoint and from a central line forward thereof is constant; and in Figs. 1 to 6 the said line will be a straight line'while in'Figs. 7 8, 9 the said front line will be a curved line. Such straight and curved lines are known as regular lines.

It will now be obvious that other forms of die forming surfaces such as hemi-ellipsoids, elliptical paraboloids, and parabolical hyperboloids all being quadrics or conicoid envelopes of intersections of conics of revolution may be produced with out departing from my invention and I desire to be understood as claiming all such.

I claim: 7

1. As an article of manufacture, a tool for forming thin surfaces comprising a forming face every point on which is positioned such that the sum of its distances from a fixed line and from a focal point is a constant.

2. A pair of forming dies having substantially parallel forming faces spaced apart, one of said faces bein a surface every point on which is positioned such that the sum of its distances from a fixed line and from a focal oint is a constant.

The points 33 and 34 lie elliptical hyperboloids' s an article of manufacture a tool hav- BRUNO HEYMANN. 

